Wash. Rev. Code § 89.30.118
Any reclamation district created under the provisions of this chapter may change its corporate name by filing with the board of county commissioners of each of the counties in which any of the lands included within the operation of the district are situated a certified copy of a resolution of its board of directors adopted by a unanimous vote of all the members of said board at a regular meeting thereof providing for such change of name; and thereafter all proceedings of such district shall be had under such changed name, but all existing obligations and contracts of the district entered into under its former name shall remain outstanding without change and with the validity thereof unimpaired and unaffected by such change of name.
RCW 89.30.118